Common and frequent mistakes, NPEs

Error message "Manifest file missing in module"

When importing an OpenCms module sometimes you get the error message

Error uploading the module [MODULENAME].zip.
Manifest file missing in module [PATH_TO_MODULE][MODULENAME].zip.

In most of the cases the problem is, that the zip file you try to import is not the module.zip, but another zip file which includes the real module.zip

(Example from the mailing list: http://www.nabble.com/Workflow-in-v7.0.4-to17319767.html)

HowTo recognise a OpenCms module by its name

OpenCms modules are normally named in java package syntax with the version as suffix.

org.opencms.workplace_7.0.4.zip